Developments in technology have changed ways in which information is displayed and communicated to and between groups of people. Traditional chalkboards and whiteboards have significant drawbacks with respect to not being integrated with electronic computer and information systems. First, traditional chalkboards and whiteboards cannot be easily integrated with electronic information displays, such as liquid crystal displays (LCDs) and projectors. Second, traditional chalkboards and whiteboards require specialized writing surfaces that are compatible with chalk, dry erase markers, and/or similar writing tools. Third, information written on these types of surfaces is not easily captured electronically for computerized processing, transfer, and/or display. While some whiteboards have electronic scanning capability, traditional electronic scanning solutions can be costly for large whiteboards or surfaces as the scanning mechanism(s) must typically span the entire whiteboard, or span an entire dimension of the whiteboard, and must be designed to accomplish controlled mechanical movement of an apparatus across at least one dimension of the whiteboard.
The problems discussed above have been addressed in various ways. In one solution, a touchscreen or touchpad is overlaid across an entire electronic display surface. Touchpads typically sense a finger or stylus using one of several methods including capacitive sensing, conductance sensing, and/or using a pressure sensitive membrane of some type. These methods require that the display surface be overlaid or integrated with electrical and/or mechanical hardware which enables the surface to become touch sensitive. The cost of adding these types of touch sensing technologies to displays increases proportionally, and in some cases exponentially, with the increasing surface area of the screen. In some situations, the cost increases even further due to manufacturing yield issues associated with making devices for large devices or surfaces.
In another solution, sides or edges of electronic surfaces and/or writing surfaces are lined with optical emitters and detectors. The emitters optically direct beams of light or infrared energy across the display surface from one side to another. The detectors receive the light or energy and detect the presence of a finger, stylus, or other object on the surface through interruption or scattering of the beams of light. The emitters may be operated in various patterns, sequences, and/or pulses to make the object position determination more accurate and/or to identify the location of multiple objects on the surface. In this approach, the emitters and detectors must be permanently, or semi permanently, attached to the electronic or writing surface. This approach is not ideal because attaching the emitters and detectors to an existing surface and/or orienting them with the surface may be complex, time-consuming, unreliable, and/or expensive.